1. Field of the Invention
The present invention relates to a color filter producing method and apparatus, a color filter for a liquid crystal display, and a liquid crystal display device and an apparatus that employs the liquid crystal display device.
2. Related Background Art
Liquid crystal display devices are presently being mounted in personal computers, word processors, pachinko (or pinball) game machines, automobile navigation systems, compact television sets, etc. and the demand for and the application of such devices are increasing. However, one drawback to liquid crystal display devices is that they are expensive, and therefore, the demand and the need for means to reduce the cost of these devices has grown, year by year.
To produce a color filter for a liquid crystal display device, first, a color layer is prepared by mounting red (R), green (G) and blue (B) filter elements on a transparent substrate and arranging around each of the filter elements a light shielding, display contrast enhancing black matrix (BM). Following this, a 0.5 to 2 xcexcm acrylic or epoxy resin overcoating layer (a protective layer) is deposited on the color layer, including the filter elements in order to improve the smoothness. Following this, an ITO (Indium-Tin-Oxide) film, which serves as a transparent electrode, is deposited on the overcoating film.
As coloration of the filter elements of a color filter, there are a variety of well known conventional processes or methods available, including, as examples, dyeing, pigment dispersion, electrodeposition and printing.
When the dyeing method is employed, a glass substrate is coated with a water soluble polymer material, a dyeing material, and photolithography is used to produce a pattern having a predetermined shape in the water soluble polymer material. Then, the thus obtained substrate is immersed in a dyeing solution and colored. To produce a three-color, R, G and B, color filter layer, this process is performed once for each of the colors R, G and B, i.e., the process is repeated a total of three times.
For the pigment dispersion method, a photosensitive resin layer, wherein a pigment has been dispersed, is formed on a substrate, and a patterning process is performed to obtain a single color pattern. Then, to produce a three-color, R, G and B, color filter layer, this process is performed once for each of the colors R, G and B, i.e., is repeated a total of three times.
If the electrodeposition method is employed, a transparent electrode pattern is formed on a substrate, and the resultant substrate is immersed in an electrodeposition coating solution, containing a pigment, a resin and an electrolytic solution, to complete the electrodeposition processing for the first color (R). Thereafter, the same process is performed for the electrodeposition of the second color (G) and the third color (B), and a R, G and B color filter layer is obtained. Finally, the resultant substrate is annealed.
With the printing method, an offset printing process is repetitively used to deposit on a substrate a thermosetting resin in which a pigment has been dispersed. This process is performed once for each of the colors R, G and B, i.e., a total of three times, and thereafter, the resin is hardened to complete the formation of the R, G and B color filter layer.
A common problem, shared by all these methods, is that to apply the colors R, G and B a coloring process must be performed three times, once for each of the colors. As a result of the need to perform this repetitive processing, manufacturing costs are high. An additional, concomitant problem is that since the processes must be repeated three times, product yield is reduced.
In an effort to resolve these shortcomings, color filter producing method using ink-jet methods were disclosed in Japanese Patent Application Laid-open Nos. 59-75205, 63-235901 and 1-217320. According to these methods, ink-jet devices are used to eject inks for three different color elements, R (red), G (green) and B (blue), onto an optical transparent substrate, and the ink for each color is dried to form a colored image. According to these ink-jet methods, the formation of the filter elements R, G and B is performed simultaneously, thereby considerably simplifying the manufacturing processing and dramatically reducing manufacturing costs.
For the manufacture of a color filter using an ink-jet method, three types of heads are prepared for the ejection of the R, G and B colore inks, and as is shown in FIG. 33, to color the R, G and B filter elements for the color filter, the distance between the filter elements corresponds to the nozzle pitch of the heads. This is disclosed in Japanese Patent Application Laid-open No. 9-300664. According to this publication, since the pitch between the nozzles of the head does not match the distance between the filter elements of a color filter, the head is inclined until the nozzle pitch corresponds to the distance between the filter elements. In order to efficiently perform this operation, a method disclosed in Japanese Patent Application Laid-open No. 10-151766, i.e., a method whereby the inclination angle is adjusted by rotating the head, can be employed.
Needs have been expressed for the provision of various types of liquid crystal panels to be used for different sizes or applications, and accordingly, the demand for different types of color filters has risen. In this situation, it is imperative that a multitude of different types of low cost color filters be manufactured, and be made available within a short period of time.
Thus, through a discussion of the capability of the conventional method to be employed for the manufacture of multiple types of color filters, which are different in the sizes of the substrates, the sizes and number of the filter elements, and the color arrangements used for the filter elements, the present inventor has determined that there are several points that require further improvement.
First, according to the conventional method, the inclination angle of the head must be mechanically adjusted each time the type of color filter to be manufactured is changed. Further, since a very high degree of precision is required for this adjustment, the time required to make it is extended. Thus, there is a demand that this problem be resolved. That is, even when the color filter type is changed, it is preferable that a variety of types of color filters be manufactured in a shorter period of time.
Second, when the mechanism for rotating the angle of the head is provided as in the prior art, manufacturing costs are increased, and accordingly the overall cost of an apparatus is increased. Therefore, a demand exists that this problem be resolved. That is, it is preferable that it be possible to easily manufacture a variety of types of color filters.
As is described above, a preferable method is such that even when the type of color filter to be produced is changed, only a short time is required for the preparations (the setting of production conditions) accompanying the change, only a small number of processes must be adapted, and the various color filters can be easily manufactured at a low cost.
Furthermore, a method for manufacturing a color filter is disclosed in Japanese Patent Application Laid-open No. 9-101412. That is, as is shown in FIG. 34, to manufacture a color filter, heads and substrates are relatively scanned in the X direction, and filter elements are colored so that the filter elements in the Y direction have the same color and each of the adjacent filter elements in the X direction (the main scanning direction) have different colors. According to this method, since it is not required to match the pitch between the nozzles and the distance between the filter elements, contrary to the conditions encountered with the method in Japanese Patent Application Laid-open No. 9-300664 or 10-151766, a shorter time is required for the preparations (the setting of production conditions) that accompany a change in color filter types, and a smaller number of processes is required for the changeover.
However, in Japanese Patent Application Laid-open No. 9-101412, how production conditions are to be altered when a color filter type is changed is not specifically described.
To resolve the conventional shortcomings, it is one object of the present invention to provide a method for manufacturing multiple types of color filters at low cost.
It is another objective of the present invention to provide a method by which even when a color filter type is changed, the time required for preparations (the setting of production conditions) that accompany a change can be reduced, and various types of color filters can be easily manufactured.
It is an additional object of the present invention to provide a method for manufacturing high-resolution color filters that have no uneven colors and color mixtures, even when the type of color filter to be manufactured is changed.
To achieve the above objectives of the present invention, there is provided a color filter producing method for producing a color filter by ejecting onto a substrate ink from an ink-jet head having a plurality of nozzles arranged substantially in a first direction while relatively scanning the ink-jet head and the substrate in a second direction substantially perpendicular to the first direction so that filter elements adjacent in the second direction may be colored to have different colors, the method comprising the steps of:
performing main scanning of the ink-jet head and the substrate relatively in the second direction;
performing sub-scanning of the ink-jet head and the substrate relatively in the first direction;
ejecting ink from the ink-jet head to conduct coloration of a first color filter, during the main scanning, based on data concerning a first production;
changing the type of color filter that is to be manufactured;
changing the first production condition to a second production condition in accordance with the change in the type of color filter, and setting the second production condition; and
ejecting ink from the ink-jet head to conduct coloration of a second color filter, based on data concerning the second production condition,
wherein the first and the second production conditions are those concerning the quantity of ink ejected for each time from the nozzles, the number of times of the performances of the main scanning, and the distance covered by the sub-scanning, and
wherein three production conditions, for the quantity of ejected ink, for the number of times of the main scans and for the distance covered by the sub-scanning, are changed in accordance with the widths of the color elements of the color filter that is to be manufactured.
Further, according to the present invention, there is provided a color filter producing method for producing a color filter by ejecting onto a substrate ink from an ink-jet head having a plurality of nozzles arranged substantially in a first direction while relatively scanning the ink-jet head and the substrate in a second direction substantially perpendicular to the first direction so that filter elements adjacent in the second direction may be colored to have different colors, the method comprising the steps of:
performing main scanning of the ink-jet head and the substrate relatively in the second direction;
performing sub-scanning of the ink-jet head and the substrate relatively in the first direction;
ejecting ink from the ink-jet head to conduct coloration of a first color filter, during the main scanning, based on data concerning a first production;
changing the type of color filter that is to be manufactured;
changing the first production condition to a second production condition in accordance with the change in the type of color filter, and setting the second production condition; and
ejecting ink from the ink-jet head to conduct coloration of a second color filter, based on data concerning the second production condition,
wherein the first and the second production conditions are those concerning the quantity of ink ejected for each time from the nozzles, the number of times of the performances of the main scanning, and the distance covered by the sub-scanning, and
wherein two production conditions, for the number of times of the performances of the main scanning and for the distance covered by the sub-scanning, are changed in accordance with the color density of the filter elements of the color filter that is to be manufactured.
According to the present invention, a color filter producing method for producing a color filter by ejecting onto a substrate ink from an ink-jet head having a plurality of nozzles arranged substantially in a first direction while relatively scanning the ink-jet head and the substrate in a second direction substantially perpendicular to the first direction so that filter elements adjacent in the second direction may be colored to have different colors, the method comprising the steps of:
performing main scanning of the ink-jet head and the substrate relatively in the second direction;
performing sub-scanning of the ink-jet head and the substrate relatively in the first direction;
ejecting ink from the ink-jet head to conduct coloration of a first color filter, during the main scanning, based on data concerning a first production;
changing the type of color filter that is to be manufactured;
changing the first production condition to a second production condition in accordance with the change in the type of color filter, and setting the second production condition; and
ejecting ink from the ink-jet head to conduct coloration of a second color filter, based on data concerning the second production condition,
wherein the first and the second production conditions are those concerning the quantity of ink ejected for each time from the nozzles, the number of times of the performances of the main scanning, and the distance covered by the sub-scanning, and
wherein at least one of the production conditions, for the quantity of ejected ink, for the number of times of performances of the main scanning and for the distance covered by the sub-scanning, is changed in accordance with the type of the color filter that is to be manufactured.
Further, according to the present invention, there is provided a color filter producing apparatus for producing a color filter by ejecting onto a substrate ink from an ink-jet head having a plurality of nozzles arranged substantially in a first direction while relatively scanning the ink-jet head and the substrate in a second direction substantially perpendicular to the first direction so that filter elements adjacent in the second direction may be colored to have different colors, the apparatus comprising the steps of:
means for performing main scanning of the ink-jet head and the substrate relatively in the second direction;
means for performing sub-scanning of the ink-jet head and the substrate relatively in the first direction;
first control means for controlling a coloring operation for ejecting ink from the ink-jet head to conduct coloration of a first color filter, during the main scanning, based on data concerning a first production;
means for changing the type of color filter that is to be manufactured;
setting means for changing the first production condition to a second production condition in accordance with the change in the type of color filter to set the second production condition; and
second control means for controlling a coloring operation for ejecting ink from the ink-jet head to conduct coloration of a second color filter, based on data concerning the second production condition,
wherein the first and the second production conditions are those concerning the quantity of ink ejected for each time from the nozzles, the number of times of the performances of the main scanning, and the distance covered by the sub-scanning, and
wherein three production conditions, for the quantity of ejected ink, for the number of times of the main scans and for the distance covered by the sub-scanning, are changed in accordance with the widths of the color elements of the color filter that is to be manufactured.
Further, according to the present invention, there is provided a color filter producing apparatus for producing a color filter by ejecting onto a substrate ink from an ink-jet head having a plurality of nozzles arranged substantially in a first direction while relatively scanning the ink-jet head and the substrate in a second direction substantially perpendicular to the first direction so that filter elements adjacent in the second direction may be colored to have different colors, the apparatus comprising:
means for performing main scanning of the ink-jet head and the substrate relatively in the second direction;
means for performing sub-scanning of the ink-jet head and the substrate relatively in the first direction;
first control means for controlling a coloring operation for ejecting ink from the ink-jet head to conduct coloration of a first color filter, during the main scanning, based on data concerning a first production;
means for changing the type of color filter that is to be manufactured;
setting means for changing the first production condition to a second production condition in accordance with the change in the type of color filter to set the second production condition; and
second control means for controlling a coloring operation for ejecting ink from the ink-jet head to conduct coloration of a second color filter, based on data concerning the second production condition,
wherein the first and the second production conditions are those concerning the quantity of ink ejected for each time from the nozzles, the number of times of the performances of the main scanning, and the distance covered by the sub-scanning, and
wherein two production conditions, for the number of times of the performances of the main scanning and for the distance covered by the sub-scanning, are changed in accordance with the color density of the filter elements of the color filter that is to be manufactured.
According to the present invention, there is provided a color filter producing apparatus for producing a color filter by ejecting onto a substrate ink from an ink-jet head having a plurality of nozzles arranged substantially in a first direction while relatively scanning the ink-jet head and the substrate in a second direction substantially perpendicular to the first direction so that filter elements adjacent in the second direction may be colored to have different colors, the apparatus comprising:
means for performing main scanning of the ink-jet head and the substrate relatively in the second direction;
means for performing sub-scanning of the ink-jet head and the substrate relatively in the first direction;
first control means for controlling a coloring operation for ejecting ink from the ink-jet head to conduct coloration of a first color filter, during the main scanning, based on data concerning a first production;
means for changing the type of color filter that is to be manufactured;
setting means for changing the first production condition to a second production condition in accordance with the change in the type of color filter to set the second production condition; and
second control means for controlling a coloring operation for ejecting ink from the ink-jet head to conduct coloration of a second color filter, based on data concerning the second production condition,
wherein the first and the second production conditions are those concerning the quantity of ink ejected for each time from the nozzles, the number of times of the performances of the main scanning, and the distance covered by the sub-scanning, and
wherein at least one of the production conditions, for the quantity of ejected ink, for the number of times of performances of the main scanning and for the distance covered by the sub-scanning, is changed in accordance with the type of the color filter that is to be manufactured.